Micro-poro-elasticity of baghdadite-based bone tissue engineering scaffolds: A unifying approach based on ultrasonics, nanoindentation, and homogenization theory

Microstructure-elasticity relations for bone tissue engineering scaffolds are key to rational biomaterial design. As a contribution thereto, we here report comprehensive length measuring, weighing, and ultrasonic tests at 0.1 MHz frequency, on porous baghdadite (Ca3ZrSi2O9) scaffolds. The resulting porosity-stiffness relations further confirm a formerly detected, micromechanically explained, general relationship for a great variety of different polycrystals, which also allows for estimating the zero-porosity case, i.e. Young modulus and Poisson ratio of pure (dense) baghdadite. These estimates were impressively confirmed by a physically and statistically independent nanoindentation campaign. comprising some 1750 indents. Consequently, we can present a remarkably complete picture of porous baghdadite elasticity across a wide range of porosities, and, thanks to the micromechanical understanding, reaching out beyond classical elasticity, towards poroelastic properties, quantifying the effect of pore pressure on the material system behavior. (C) 2014 The Authors. Published by Elsevier B.V.